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| Titel |
Structure and sources of solar wind in the growing phase of 24th solar cycle |
| VerfasserIn |
Vladimir Slemzin, Farid Goryaev, Julia Shugay, Denis Rodkin, Igor Veselovsky |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107210
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| Publikation (Nr.) |
 EGU/EGU2015-6903.pdf |
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| Zusammenfassung |
| We present analysis of the solar wind (SW) structure and its association with coronal sources
during the minimum and rising phase of 24th solar cycle (2009-2011). The coronal sources
prominent in this period - coronal holes, small areas of open magnetic fields near
active regions and transient sources associated with small-scale solar activity have
been investigated using EUV solar images and soft X-ray fluxes obtained by the
CORONAS-Photon/TESIS/Sphinx, PROBA2/SWAP, Hinode/EIS and AIA/SDO
instruments as well as the magnetograms obtained by HMI/SDO. It was found that at
solar minimum (2009) velocity and magnetic field strength of high speed wind
(HSW) and transient SW from small-scale flares did not differ significantly from
those of the background slow speed wind (SSW). The major difference between
parameters of different SW components was seen in the ion composition represented
by the C6/C5, O7/O6, Fe/O ratios and the mean charge of Fe ions. With growing
solar activity, the speed of HSW increased due to transformation of its sources –
small-size low-latitude coronal holes into equatorial extensions of large polar holes. At
that period, the ion composition of transient SW changed from low-temperature to
high-temperature values, which was caused by variation of the source conditions and
change of the recombination/ionization rates during passage of the plasma flow
through the low corona. However, we conclude that criteria of separation of the SW
components based on the ion ratios established earlier by Zhao&Fisk (2009) for
higher solar activity are not applicable to the extremely weak beginning of 24th
cycle.
The research leading to these results has received funding from the European
Commission’s Seventh Framework Programme (FP7/2007-2013) under the grant agreement
eHeroes (project n°284461, www.eheroes.eu). |
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